Process for the preparation of terpineol



Patented Sept. 5, 1950 f PROCESS FOR THE PREPARATION'OF v H TERPINEOL Sereno G. Norton,'iBrunswick, Ga., assignor -to Hercules Powder Company,'Wilnrington, D el., a v

corporation of Delaware No Drawing. Application July 10,1947, 7 Serial No. 760,119

Thisinvention relates to the process of partially dehydrating terpin hydrate to form terpineol. t

It is well known that terpin hydrate maybe 7 4 Claims. (ol. 2s0,-631.5)

Example I I 1 Fifty 'parts' of a purified terpin hydrate were 1 dissolved in 2500 parts of distilled water which had previously been brought to a pH of 3.4 by

dehydrated to terpineol by treatment withphos- 5 bubbling carbbn dioxidethrough it The P d Sulfuric acid In farrying 9 tion was heated at 50 pounds gauge pressure to' this proceiss a secoilrldgryhdehyga bt ta g f 153 C.' for3 hours. The vapors were then re l F n as a F 6 9 w leased through a valve and condensed, the ter: gyingrazurgo tefilnfgtingnlllgrgil gsgge131E 3 1O pineiol formed; being thus steam distilled from the reac ion mix ure; The erpineol oil layer "was i ed y gfi q e i t haive gf i-l l separated and dried and was found to have are- 0 increase e V f 911311190 W 19 1S a fractive index at 20 C. of 1.4808 indicating that commercially valuableimaterial. Most of these little dehydration to t e hyqroca'rbon'vhad 0 methods requ e either elaborate Processmg P- curred (the refractive index of typical pure mixed erations or the utilizationof additional costly terpineols is'lABlO). materials. NoW in accordance with thisinvention, it has Example been discovered that terpin hydrate may be de- Flfty p l 0f p d e l hy ate a d 2500 I hydrated to 'terpineol, without any appreciable parts f s led Water, adJuSted to 9; D 0f amount of the secondary dehydration occurring, by to remove P t f e SSO ed by heating the terpin hydrate with water acidibOII d oxlde were heatedat 5 pounds gauge D S- lied to a pH of 3.4V to 6.9 with dissolved carbon surefio 153 The vapors e dioxide; at a temperature of about 117 to 200 C. then released thro h a v ve Y and 1 1d n d.' and under a pressure of about 40 to 200- pounds i terpmeol h refractwe lPdex t. per square inch. Not only is this process a simg pg g hi -gfi r ggr x a l l ng lghat sggbstait alllg'dno ple and efficient method for dehydrating terpin 0 a P WT]: hydrate to terpineolin'high 'yields'without pro- 33; gggafiggzfg i gggg iggr gs iu gg, ducing any appreciable amount-of terpene hydro- 1 i v g carbon, but it makes possible the recovery, in'the Sport m pe f p complete m? form of the valuable terpineoL'of terpin hydrate Ex mme I from water solutions containing small percent- 7 v H ages of terpin hydrate. In many operations in Fifty Part3 f P i d t p y te re t naval Stores t y; t te Water n heated in an autoclave with 2500 parts of freshly tainsa small percentageiof terpin hydrate, which; dlstllled r, having a pH of 6.0 due to the disbecause'of its lowconeentr'a'tion, is not recover 5 solved carbon dioxide, for 1 hour at 100 pounds able and is, therefore; lost. It has now been gauge pressure and a p a e of 168 C. The found that when this Waste Water; containing Vapors were Q released llhrough l and dissolved carbon dioxide, heated under the condensed. The terpmeol o11 layer which was'reabove described condmcnsa the "terpin' hydrate 40 covered anddned amounted to 31.3 parts and had in is converted toterpinedl which may be 0 airefract ve index at 20 C. of 1.4771. covered, resulting in great economies to the in- Example IV I dustry. Another important advantage of this process is that the terpin hydrate which is disg fig agiif fig ggg gfi g i 3 g: gem s1ved spewed in crude synthetic Pine of 3 s by bubbling'carbo: dioi de t r froighfizv re such as that derived from tu fnenti e by h drating in acid mixture; in which the terpin hydrate heated m an autoclavi for 1 hour at go gpounds' is present to'the extent of 2-3 may be .convertgi zg i zggg i gg gg ggg f gg 3 ed to terpineol by this process without causing was Steam distilled off with 1000 I e r parts of water. the u dehydratlgnpf the Pme 011 t A yield of 28 parts of terpineol having a retrac Pene hydrocarbon i. tive index at 20 c "4791 The following examples are demonstrative of f i was obtamed' i the process in accordance with this invention. 1 V wmi V All parts and percentages lare by weight unless Example IV was repeated except that the disotherwise indicated. tilled water was brought to a pH of 6.0 by bubbling carbon dioxide through it and the reaction was carried out at a temperature of 68 C. A yield of 31 parts of terpineol having a refractive index at C. of 1.4771 was obtained.

Example VI Two hundr ed partssoff terpin hydrate and 2000 parts of a distilled. water, adjusted to a pH of 5.2 by means of carbon dioxide, were charged to an autoclave and heated to 155-156 C. for minutes at 6065 pounds gauge pressure. ,The'charge was then allowed to distill through a valve and,

112 parts of oil representing a yield of of the theoretical yield was obtained. "Thisoil had a refractive index at 20 C. of "1.4783, a specific gravity at 15.5 C. of 0.9374, and was found to contain 190% tertiary alcohols.

Example VII A mixture of 5675 parts .of technical grade ter charged into an autoclave and heated to 163 C. for 15 minutes at pounds gauge pressure. The autoclave was then allowed to cool and the oil was separated and dried. Analysis of the oil showed that it contained no terpin hydrate, indicating that the terpinhydrate had been entirely-converted to terpineol. The refractive index at 20% C. of the oil before treatment was 1.4772 and after treatment was 1.4775, thus showing that no breakdown of the pine oil to terpene hydrocarbons had occurred.

The dehydration treatment when carried out in accordance with this invention converts terpin hyretical yield-l. .Ithad a refractive index at.29

(Lei 1.4818,:aspeeific gravity.at C. of 9.9360,

and:centained 99.-3 tertiaryalcohols, indicating that the terpineol was practically free from any monocyclic terpene hydrocarbons. Some unconverted terpin hydrate'remained in the autoclave indicating that the =terpin hydrate which was in solution in the water was entirelyconverted.

" Example LVIII -'A;p1ant waste Water .was found to contain-0.4 terpin hydrate and had a pH of "5.0 due -.to dissolved carbon dioxide. This waste water, 56,750 parts-was heated to 1:181-C.. under 150 pounds gauge'pressure. As soon as this temperature and pressure had been reached, the vapors were released through :a'pressure valveand condensed. Five percent of thecharge distilled off {and carried with it all of the recovered terpineol. The terpineol recovered from this waste water amounted to 171 parts (92.5% of .the theoretical yield) and had a refractive index at 20 of 1.4791.

Waste water from the stills, i'having a pH of 3.8r,;due to dissolved carbon dioxide, was -'charged to anaautoclaue and heated (to 10. under DQ mdsgauge-pressure. Assoon :as this temperature had been reached, the heating 'wa-s discontinued and the batch. allowed to distill. A total of 2.25 parts of oil was recovered from 1125 arts ao'f this waste water. on analysis the p11 was round to have a re'fraetive index at 20 of 1.48%, a. speeifiegravity 'at 15.5" oer b59304, and contained ssfiys tertiary alcohols.

Q .lJacamplaX A crude hydrated Ftur p'e-ntine"(synthetic pine oil-vfrom rthexao'etone h'ydratic n process") was found .toucontain T254896 terpin hydrate. Fifteen hundred parts of this prudehydrated turpentine and 500 parts of distilled water, which had a pH of due to -'iissolved carbon "dioxide, were drateintoterpineol without the formation of any I appreciable amounts of terpene hydrocarbons. The terpineol formed is a mixture of terpineols in which alpha-terpineol usually predominates. Any source of terpin hydrate may be used to prepare terpineol in accordance with this invention.

The process is particularly advantageous in providing a method of recovering terpin hydrate present in waste water, ,etc., thus resulting ,in more economical plant operations. It is also .01 importance in converting the small amounts .of terpin hydrate .in synthetic pine oil to terpineol without increasing the terpene hydrocarboncontent of thepine oil as do theprior art dehydrat I ing agents.

The dehydration reaction may be carried out at ,a temperature of about "117 C. 'to about 200 C. at a pressure of from about 40 pounds ,per

square inch to 200 pounds per square inch. The optimum conditions for the reaction are a temperature of 160 C. to 190 C. at a'pressure of 75 to .170 pounds per square inch. When operating at the higher temperatures -and pressures it .is f

usually desirable to shorten the period of heating,

since continued heating at the higher temperatures is apt to cause further dehydration of the ter-' pineol to the undesirable terpene hydrocarbons. However, at lower temperatures and pressures, a longer heating period is required to convert all of the-terpin hydrate into terpineol as may be seen For example, while from 2 to 3 hours may be required at lower from the foregoing examples.

temperatures, a few seconds is all that is necessary at the higher temperatures.

The process in accordance with this invention maybe carried out as a batch or continuous process. Thus, if crystals of terpin hydrate are to be converted, the batch "process is probably T However, in :the treatment of waste preferable. water, or other aqueous solutions of terpin hydrate, the process is of particular value since it may be carried out as a continuous process. For example, the water may be pumped through a coil or vessel under pressure and heated to temperatures of 180-200 vC. and then immediately discharged through a valve to atmospheric pressure or a portion of the water maybe distilled off continuously by bleeding through a suitable vapor line and. condenser. The steam which flashes off when the water isdischarged carries the terpineol, which may then be recovered :by condensing and separating it from the Water. ,A continuous process may also be employed for .the treatment of synthetic pine oil .to convert the small percentage of terpin hydrate :in the spine oil to terpineol.

The concentration of terpin hydrate in the reaction mixture may vary over a wide range. .80-

dissolved terpin hydrate 'may be present, in

The dehydration treatment 'in accordance with this invention is carried out by utilizing carbon dioxide as the acidifying reagent. The pH of the carbon dioxide solution, 1. e. the solution of carbonic acid, may vary from 3.4 to 6.9 and preferably from about 4.0 to about 6.8. At a pH of 7.0, i. e. a neutral solution, no conversion takes place, but with the introduction of only a small amount of carbon dioxide, even to a pH of 6.9, conversion readily takes place. The carbonic acid solution may be formed by simply bubbling carbon dioxide through water until the desired pH is attained. In normal plant operations, the still waste water contains a suificient amount of dissolved carbon dioxide to carry out the reaction. Usually such water, containing low percentages of terpin hydrate, has a pH of 5.0 to 6.0 due to dissolved carbon dioxide.

As pointed out above, the use of carbon dioxide as the acidifying agent and a pH of 3.4 to 6.9 makes it possible to dehydrate terpin hydrate to terpineol without the further dehydration to terpene hydrocarbons. It also provides a method of converting terpin hydrate to terpineol, from solutions where the terpin hydrate has otherwise not been recoverable. Thus, the process of this invention has made possible economies in operation not formerly realized and also has pro- 9 vided a simple operation of converting terpin hydrate to terpineol without the formation of any appreciable quantities of the undesirable monocyclic terpene hydrocarbons which are normally obtained in the dehydration of terpin to terpineol.

What I claim and desire to protect by Letters Patent is:

1. The process of preparing terpineol from terpin hydrate which comprises heating terpin hydrate with a solution of carbon dioxide, having a pH of about 3.4 to about 6.9, to a temperature of about 117 e. to about 200 c. at a pres: sure of about 40 to about 200 pounds per square inch, until conversion is substantially complete, and recovering the terpineol from the mixture.

2. The process of preparing terpineol from terpin hydrate which comprises heating terpin hydrate with a solution of carbon dioxide, having a pH of about 4.0 to about 6.8, to a temperature of about 160 C. to about 190 C. at a pressure of about to about 170 pounds per square inch, until conversion is substantially complete, and

recovering the terpineol from the mixture.

3. The process of converting the terpin hydrate present in Waste water to terpineol, which comprises heating said waste water, containing dissolved carbon dioxide, to a, temperature of about C. to about 190 C. at a pressure of about 75 to about pounds per square inch, distilling oil and condensing the vapors, and separating the condensed terpineol from. the water.

4. The process of converting the terpin hydrate present in synthetic pine oil, which comprises heating said pine oil with a solution of carbon dioxide, having a pH of 3.4 to 6.9, to a temperature of about 160 C. to about C. at a pressure of about 75 to about 170 pounds per square inch.

SERENO G. NORTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Bhushan et al.: Indian Turpentine-. C. A. 39 (1945) col. 4065-4066 :(1 page). 

1. THE PROCESS OF PREPARE TERPINEOL FROM TERPIN HYDRATE WHICH COMPRISES HEATING TERPIN HYDRATE WITH A SOLUTION OF CARBON DIOXIDE, HAVING A PH OF ABOUT 3.4 TO ABOUT 6.9, TO A TEMPERATURE OF ABOUT 117*C. TO ABOUT 200*C. AT A PRESSURE OF ABOUT 40 TO ABOUT 200 POUNDS PER SQUARE INCH, UNTIL CONVERSION IS SUBSTANTIALLY COMPLETE, AND RECOVERING THE TERPINEOL FROM THE MIXTURE. 